Self-Knowledge & Semantic LuckComments on P. Boghossian, What the Externalist Can Know A Priori

Stephen YabloU. of Michigan, Ann Arboryablo@umich.edu

I. Paul's paradox

There is no prize in philosophy for the shortest a priori proof of an external
world; longest would be more like it. If a prize were to be given, though, it
would have to go to the argument just set out:

(1) If I have water-thoughts, then water exists.
(2) I have water-thoughts.
(3) So, water exists.

That is, this argument would win the prize if it worked: if, in particular, its
premises were a priori knowable. Paul maintains that it doesn't work. What we
have is rather a paradox in which two enormously plausible hypotheses --
one backed by privileged access, the other by externalism about content -- are
found to entail an incredible result, viz. the a priori knowability of there
being such a thing as water.

II. Saul's paradox

Before Paul's paradox, there was Saul's. Saul's paradox is in a way more the
urgent of the two, because it casts doubt on the compatibility, not of calling
(1) and (2) a priori, but of calling them (or statements very like them)
true. Here is a passage from Naming and Necessity:

it is said that though we have all found out that there are no
unicorns,... [u]nder certain circumstances there would have been
unicorns. And this is an example of something I think is not the case...
Perhaps according to me the truth should not be put in terms of saying that it
is necessary there should be no unicorns, but just that we can't say under what
circumstances there would have been unicorns.[1]

Two things are said here to be "said": first, that there aren't any
unicorns, and second, that under certain circumstances there would have been
unicorns. It is only the second claim that Kripke disputes. He takes it for
granted that unicorns don't exist; this indeed is why "unicorn"-sentences lack
truth conditions, and why unicorn-thoughts (which presumably need truth
conditions to exist) are ruled out entirely.

Now, suppose it is really true that for there to be X-thoughts,
there have to be Xs.[2] Then
the problem is this. What is to prevent a philosophically reflective 18th
century thinker -- what for that matter is to prevent you or I -- from proving
the existence of caloric by essentially Paul's argument:

(1') If I have caloric-thoughts, then there is caloric. (2') I have caloric-thoughts.(3') So, there is caloric.

Since the conclusion is false -- there is no caloric -- one of the premises
must be false as well. Which one? I call this a paradox because one has, as
Kripke likes to say, a considerable feeling that both premises properly
understood are correct.

Having just asserted that there is no caloric, the second premise will be
hard for me to deny; the thought that there is no caloric is a caloric-thought
if anything is. And I have other caloric-thoughts as well: people used to
believe in caloric; if there is caloric, then so much the worse for the atomic
theory of heat.

But the first premise is hard to argue with too. A thought is something
with truth conditions -- it is something that can be compared to a possible
world and found to be either true of that world or false of it. And in the
absence of any real caloric to set the standard, there seems to be just no
saying which of the caloric-like substances in other possible worlds are
relevant to the counterfactual truth-values of my caloric-thoughts.

III. Kripkean vs. Fregean truth conditions

The Kripke passage paints a picture of unicorn-thoughts as true without
possessing truth conditions. How is this possible? A thought is true, it
would seem, only if it puts conditions on reality, which conditions are in fact
met. These conditions though could hardly be other than the thought's truth
conditions. And wasn't it truth conditions that were supposed to be going
missing on the Kripkean picture?

An analogy may help. Suppose I introduce H as a predicate that, no
matter how the world may turn out, is to be true of all and only the hedgehogs.
Now consider the statement, or thought, that there are Hs. Are you in a
position to compute its truth conditions?

Not in the sense at issue in the Kripke passage, for I haven't told you
anything about what it takes for H to be true of a counterfactual
object. (And I'm not going to; the whole meaning of H has now been
explained.) And yet there would seem to be little doubt that the thought is
true. Because whatever there are Hs says or doesn't say about other
worlds, this world it describes as containing hedgehogs. Here then is a
case of a truth that is lacking in truth conditions.

But wait a minute, you say. Of course the thought that there are Hs
has truth conditions; it is true under the condition that hedgehogs exist.

There is clearly something to this objection. The thought has truth
conditions of a sort: its (actual) truth-value depends on whether such
and such conditions are (actually) met. It remains, though, apparently, that
the thought lacks truth conditions of the sort intended by Kripke: conditions
that determine whether a (possibly counterfactual) world is correctly
described by the thought. To have some language for this unusual state
of affairs, let's say that there are Hs has "Fregean" truth conditions,
but little or nothing in the way of "Kripkean" ones.

IV. Consequences for the paradoxes

What does this tell us about Saul's paradox? If "having a thought to the
effect that there is caloric" means "having a thought with the Kripkean,
or modalized, truth conditions that there is caloric," then (1') looks true;
without actual caloric to set the standard, how can there be a fact of the
matter about caloric's counterfactual career?[3] But (2') is false. I am not thinking that there
is caloric because my "thought" leaves it wide open which worlds are
caloric-worlds.

If on the other hand we are talking about "having a thought with the
Fregean, or actualized, truth conditions that there is caloric," then
matters are reversed. I am indeed thinking that there is caloric -- so (2') is
true -- but, (1') to the contrary, my ability to do this is not hostage to the
real existence of the stuff.

Will the same approach work with Paul's paradox? Take first Kripkean
water-thoughts, or water-thoughts individuated by their Kripkean truth
conditions. A priori reflection suggests that these require actual water, as
stipulated in (1). But that I am thinking a Kripkean water-thought is, it may
be argued, not something I can tell a priori. So (1) is a priori but (2) is
not.

If we switch now to the Fregean truth conditions of my thought -- the way
its truth-value in the actual world depends on the actual facts -- this does
seem to be a priori detectable. Even the full Fregean meaning of my
thought -- the way its truth-value across all worlds[4] depends on the actual facts -- is a priori knowable.
But so what? Thoughts individuated by their Fregean truth conditions, or
meanings, don't call a priori for actual water. This time then it is only (2)
that's a priori.

V. Let's be Kripkean

Terrific; except that all this time we have been walking into a neatly laid
incompatibilist trap. Here is what the incompatibilist will say:

I don't care if Fregean thoughts are a priori knowable, because
Fregean thoughts are not externalist in my sense. Your view appears to
be that externalism and privileged access can both be true, but not of the
same thoughts. Why should I disagree?

This reply forces us to put the Fregean notions aside for a bit, and look
again at Paul's claim that Kripkean truth conditions go missing on Dry Earth.
(Truth conditions are henceforth Kripkean; the one Fregean notion that will
recur is "meaning," and that not until the last section.)

One thing is clear: if this be Dry Earth, then the great majority of worlds
are not classifiable either as containing water or lacking it. It's the next
step that bothers me. Does it really follow that there is water is
lacking in truth conditions?

That depends. It probably does follow, if truth conditions are seen as
singular propositions made up inter alia of full-blooded properties; in the
absence of water, there can be no full-blooded property of being water,
which is curtains for the proposition.

But the singularist conception is a surprising one in a context where
truth-conditionality is being treated as a condition of thought. After all, the
capacity for water-thought is intuitively quite independent of ontological
disputes about what sorts of properties there may be, including disputes about
whether properties exist at all. I suppose one could say: let's have a
pleonastic conception of properties on which the needed properties come for
free. But they come for free only when the predicate is suitably meaningful,
and the meaningfulness of "water" on Dry Earth is just what we are arguing
about.

What sort of object should play the role of truth conditions, if not a
full-blooded singular proposition? The answer is that any object will do that
encodes the possibility of interrogating a world on such matters as whether it
contains water; that's what it takes for water-thought, hence that's all that
can be asked of truth conditions considered as a requirement of such
thought.[5] It seems to me that the
encoding role is most directly and efficiently played by (truth conditions
conceived as) rules or recipes for classifying worlds. Singular propositions
can serve in some cases as handy repositories of classificatory information.
But if we're talking about truth conditions in the sense essential to thought,
it's the rule that matters.

VI. Degrees of taxonomic power

Now rules, as we know, are apt to have blind spots: sometimes big ones. The
rules defining "true," for example, leave us hanging as often as they deliver a
verdict; there are fully as many paradoxes and related pathologies as secure
truths and falsehoods. That semantical thought is somehow nevertheless possible
suggests a conjecture: "there is water" does have truth conditions on
Dry Earth,[6] but truth conditions that
lack resolving power as between cases. A few utterly dry worlds are ruled out,
but on most worlds they just fail to pronounce.[7]

The truth analogy has its limits, because the sniffing out of paradoxes has
a significant a priori component. A better analogy is with Carnap's semantics
for theoretical terms in Testability & Meaning.[8] He lays it down that an object immersed in water is
soluble iff it dissolves; and that chemical analogues of solubilia
(insolubilia) are themselves soluble (insoluble). As he is quick to point out,
this leaves a great many cases completely undecided; for all we can tell a
priori, it leaves every case undecided.

These empirical uncertainties notwithstanding, Carnap has, it seems,
infused the word "soluble" with substance enough to allow for
solubility-thoughts -- and hence with substance enough for truth conditions, to
the extent that solubility-thoughts require them. One does not feel the truth
conditions of this is soluble to be dwindling away into nothing as the
number of actual immersals declines. One feels rather that they are pronouncing
on fewer and fewer cases, and to that extent falling short of their destiny as
truth conditions. But thoughts with underperforming truth conditions are still
thoughts.

VII. Paradox redux

You can guess where this is heading. If we are unlucky enough to be living
on Dry Earth, then as Paul says, there is no (full-blooded) property of being
water. That doesn't in itself make nonsense of the question "which actual and
counterfactual stuffs deserve to be described as water?" It doesn't rule out
that "there is water" puts a condition on worlds, albeit a condition with less
taxonomical power than might ideally be wanted. And it does have some
taxonomical power, for it rules negatively on Dry Earth.

The proposal then is that the compatibilist should deny that
water-thoughts a priori require water. But while this may be enough to counter
the paradox as presented (specifically the first premise), what about the
following variant, where "taxonomical" means "has a good deal of taxonomical or
classificatory power":

(1*) If I have taxonomical water-thoughts, there is water.(2*) I have taxonomical water-thoughts. (3) There is water.

I want to claim that the revamped paradox just reverses the problem with
the original one. It may be true, and true according to externalism, that (1*)
is a priori.[9] But privileged access
ought not to be understood as making (2*) a priori. The hypothesis that
I'm thinking taxonomical water-thoughts is too close to the hypothesis
that there is water for one to be a priori and the other not.

VIII. Knowing what

At this point the original question -- how am I to tell without empirical
research whether I'm thinking? -- begins to transmogrify itself into a
more familiar one: how am I to tell without empirical research what I'm
thinking?[10] To claim a priori
knowledge of my thoughts, in particular of their truth conditions, I should at
a minimum be able to tell whether these conditions possess any genuine bite.

Such an argument seems only common sense. But it trades on a very
particular conception of "knowing what" -- a conception that may itself seem
only common sense, but which requires scrutiny. I call it absolutism
about knowing what:

knowing what X is is knowing inherently important facts
about what X is, that is, X's identity or essence or nature.

If the truth conditions of my thought are not terribly taxonomical, then
that would seem to be an important fact about their nature -- the kind of fact
that, according to absolutism, someone who knows what the truth conditions are
ought to be cognizant of. Since I can't attest a priori to their resolving
power, it seems that I don't know a priori what the truth conditions of
there is water really are.

Is absolutism correct? A look at a few of its consequences will help us
decide. It follows from absolutism that (i) facts about X's nature are
crucial to knowing what it is; (ii) facts not about X's nature are
irrelevant to knowing what it is; and (iii) the same facts are relevant to
knowing what X is regardless of how it is described.

All of this seems highly debatable. As against (ii), to know what magenta
is, you have to know how it makes things look, even if magenta is an
intrinsic property of external objects with no essential relation to human
experience. Similar remarks apply to the north pole (it's on top of the world),
LSD (it gets you high), dirt (it's cheap), and the Earth (it's the planet we
live on). To go by (i), only a philosopher can tell you what the least prime
number is; the mathematicians talk a good game, but they aren't even decided
whether two is a set. As for (iii), squareness and diamond-shapedness are the
same property, but different recognitional abilities are required to know what
they are. Whoever doesn't know what salt is must have been living under a
rock, but sodium chloride is a different story. The anhedonic physiologist
knows what p-fiber firings are but not pleasure, even if pleasure and p-fiber
firings are one and the same.

Of course, the application that interests us is to knowledge of truth
conditions. But absolutism seems wrong here too. I know what the truth
conditions of Goldbach's conjecture are and yet I am ignorant of as basic a
fact as this about them: whether they are necessary or impossible.[11] (Think too of theoretical identities in
science, genealogical conjectures, etc.) If I can get by without a priori
knowledge of one "basic metaphysical fact" about truth conditions, their
satisfiability, why not another, the fact of how taxonomical they are?

IX. A non-absolutist alternative?

After all this shirking of epistemic obligations, someone might ask: what
do I have to know to know the truth conditions of my thought? As an
alternative to the "metaphysical" conception just scouted, suppose we try the
following:

(*) I know a priori what the truth conditions of my thought are
iff I know a priori that it has the truth conditions that P -- for
P an appropriate (?!?) sentence of my language.[12]

This leaves the incompatibilist one final opening. To know a priori that
my thought has the truth conditions that P, I need to know a priori that
it doesn't have the (alternative) truth conditions that Q. And if
externalism is correct, then for some values of Q, I don't. E.g., for
all I can tell a priori, the thought I express with the words "there is water"
might be true under the condition that there is XYZ.[13]

Here is how I would like to be able to respond; the details are
still under construction. A priori knowledge resembles ordinary knowledge in
an important respect: it requires us to rule out some counterpossibilities but
not all the counterpossibilities there are. This is clear from consideration
of the simplest examples. I know a priori that my location is here, but I
don't know a priori that my location is not Kinshasa, despite the fact
that being here (in Ann Arbor) is strictly incompatible with being in Kinshasa.
I know a priori that Kabila is Kabila, but I don't know a priori that Kabila
isn't Mobutu, despite the fact that being Kabila is incompatible with being
Mobutu.

And now a speculation, offered in the spirit of something that would be
neat if true: the alternatives I have to rule out a priori, to know a priori
that I am thinking the Kripkean thought that there is water, are ones that I
can rule out a priori just by virtue of my a priori grasp of Fregean
meanings (as described at the end of section IV).

To see why this is not completely insane, suppose we ask why I don't
have to know a priori about not being in Kinshasa to know a priori about being
here.

Answer: for all I can tell a priori, "I am here" and "I am in Kinshasa"
have the same Kripkean truth conditions; whence for all I can tell a priori,
"my thought has the truth conditions that I am here" and "my thought has the
truth conditions that I am in Kinshasa" have compatible Kripkean truth
conditions.

Obviously, though, I cannot be required to rule out a priori scenarios that
are, for all I can tell a priori, compatible with what I think, as a
condition of that thought's constituting a priori knowledge. This would empty
the category of a priori knowledge altogether; even logical truths like
Kabila = Kabila would lose their a priori status, since I cannot rule
out a priori that Kabila = Mobutu. I conclude that

(**) To know a priori that A, I have to know a priori
that not B -- but only in cases where B is a priori incompatible
with A.

Applied to knowledge of truth conditions, (**) means that

(***) To know a priori that my thought has the truth conditions
that P, I have to know a priori that it doesn't have the truth
conditions that Q -- except in cases where it is a priori possible (ie.,
not a priori false) that P and Q have the same truth
conditions.

The connection between (**) and (***) is just this; the cases where it is a
priori possible that P and Q agree in their truth conditions are
precisely the ones where B = "my thought has the truth conditions that
Q" fails to be a priori incompatible with A = "it has the truth
conditions that P."

Now, do I have the a priori knowledge that (***) requires of me? I see no
reason to doubt it. If P and Q are a priori different in their
truth conditions, it will be a priori too that no P-thought has the
truth conditions that Q. To infer a priori that my thought
doesn't have the truth conditions that Q, I will need to know a priori
that my thought is a P-thought. But that is the commonsense view; it is
the incompatibilist's job to undermine it, not mine to shore it up.

As a matter of fact, though, it can be shored up, if we allow ourselves an
assumption to which incompatibilists are not per se opposed. The assumption is
that I have priori knowledge of Fregean meaning: of how the truth
conditions of my thoughts and sentences depend on the actual-world facts.[14] Why should incompatibilists deny this?
Fregean meaning is intrinsic and their problem is about extrinsic
content specifically.

Suppose then that I am granted a complete a priori grasp of the Fregean
meanings of my thoughts, and of relevant sentences of my language. This tells
me, for each Q meeting the proviso of (***), that however the actual
world comes out, my thought never acquires the truth conditions that Q.
From this I conclude a priori that I am not thinking that Q. Any block
raised by (***) to my knowing a priori that I am thinking that P is thus
removed.

So much is to defend against an objection. I can make a positive a
priori case that I am thinking that P by the same method: "noticing"
that my thought comes out with the truth conditions that P on every
hypothesis about actuality. By (*), nothing more is required for a priori
knowledge of what it is that I am thinking. The apparent result is that a
"complete" a priori grasp of my Fregean thoughts[15] provides me with "ordinary" a priori knowledge of my
Kripkean ones.

[5] Up to and including
singular-proposition-like objects adapted to avoid Paul's worry about the lack
of a property.

[6] E.g., a world contains water if there is
a unique watery stuff on Dry Earth which it sufficiently resembles, and lacks
water if it is thoroughly dry. (This is crude.)

[7] The similarly pathetic truth conditions
of "there is caloric" rule out different worlds, which is enough to mark the
two as distinct. (I assume the physics of heat on Dry Earth is exactly as
here.) They are distinct too in being poised to rule different worlds
in, given less unfavorable empirical conditions.

[9] I have doubts about the a priority of
(1*) too, because I suspect that "water" could stand on Dry Earth for a
superficial phenomenological kind. "Natural kind" terms stand for the most
natural kind available; they "seek their own level" in Kripke's phrase. That
some of "air," "earth," "fire," and "water" strike us now as more natural-kindy
than the others reflects no special semantic ambition on their part, but just that
they are the ones that got lucky. (I grant that there could be terms -- "!!WATER!!," maybe? --
that denote natural kinds or nothing; and so I am not pressing the point. Lest anyone try to press from the other side, I would note that our "intuition of privileged access" to Kripkean water-thoughts quickly lapses when !!WATER!!-thoughts are thrown into the equation.)